Abstract
Porous materials with open metal sites have been investigated to separate various gas mixtures. However, open metal sites show the limitation in the separation of some challenging gas mixtures, such as C2H2/CO2. Herein, we propose a new type of ultra-strong C2H2 nano-trap based on multiple binding interactions to efficiently capture C2H2 molecules and separate C2H2/CO2 mixture. The ultra-strong acetylene nano-trap shows a benchmark Q(st) of 79.1 kJ mol(-1) for C2H2, a record high pure C2H2 uptake of 2.54 mmol g(-1) at 1x10(-2) bar, and the highest C2H2/CO2 selectivity (53.6), making it as a new benchmark material for the capture of C2H2 and the separation of C2H2/CO2. The locations of C2H2 molecules within the MOF-based nanotrap have been visualized by the in situ single-crystal X-ray diffraction studies, which also identify the multiple binding sites accountable for the strong interactions with C2H2.